U.S. patent number 9,414,345 [Application Number 13/825,028] was granted by the patent office on 2016-08-09 for method and an arrangement for sharing of a first cell radio network temporary identifier.
This patent grant is currently assigned to Telefonaktiebolaget LM Ericsson (publ). The grantee listed for this patent is Anna Larmo, Mats Sagfors, Riikka Susitaival, Johan Torsner, Stefan Wager. Invention is credited to Anna Larmo, Mats Sagfors, Riikka Susitaival, Johan Torsner, Stefan Wager.
United States Patent |
9,414,345 |
Larmo , et al. |
August 9, 2016 |
Method and an arrangement for sharing of a first cell radio network
temporary identifier
Abstract
method and an arrangement (800) in a radio network node (140)
for sharing of a first Cell Radio Network Temporary Identifier,
referred to as "C-RNTI" between at least a first and a second
communication device (110, 120) are provided. The radio network
node (140) receives a first random access preamble from the first
communication device (110). Furthermore, the radio network node
(140) associates the first C-RNTI to the first communication device
(110), in response to the first random access preamble. The radio
network node (140) receives a second random access preamble from
the second communication device (120). Moreover, the radio network
node (140) associates the first C-RNTI to the second communication
device (120), in response to the second random access preamble,
while the association of the first C-RNTI to the first
communication device (110) is maintained. A method and an
arrangement (900) in a first communication device (110) for
enabling sharing of a first Cell Radio Network Temporary Identifier
between at least the first communication device (110) and a second
communication device (120) are provided.
Inventors: |
Larmo; Anna (Espoo,
FI), Sagfors; Mats (Kyrkslatt, FI),
Susitaival; Riikka (Helsinki, FI), Torsner; Johan
(Kyrkslatt, FI), Wager; Stefan (Espoo,
FI) |
Applicant: |
Name |
City |
State |
Country |
Type |
Larmo; Anna
Sagfors; Mats
Susitaival; Riikka
Torsner; Johan
Wager; Stefan |
Espoo
Kyrkslatt
Helsinki
Kyrkslatt
Espoo |
N/A
N/A
N/A
N/A
N/A |
FI
FI
FI
FI
FI |
|
|
Assignee: |
Telefonaktiebolaget LM Ericsson
(publ) (Stockholm, SE)
|
Family
ID: |
45893421 |
Appl.
No.: |
13/825,028 |
Filed: |
September 27, 2010 |
PCT
Filed: |
September 27, 2010 |
PCT No.: |
PCT/SE2010/051036 |
371(c)(1),(2),(4) Date: |
May 03, 2013 |
PCT
Pub. No.: |
WO2012/044211 |
PCT
Pub. Date: |
April 05, 2012 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20130223370 A1 |
Aug 29, 2013 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
60/00 (20130101); H04W 74/00 (20130101); H04W
8/26 (20130101); H04W 76/11 (20180201); H04W
74/0841 (20130101) |
Current International
Class: |
H04W
60/00 (20090101); H04W 4/00 (20090101); H04W
8/26 (20090101); H04W 76/02 (20090101); H04W
74/00 (20090101); H04W 74/08 (20090101) |
References Cited
[Referenced By]
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EP |
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2007052968 |
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May 2007 |
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WO |
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2008038983 |
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Other References
3GPP TSG RAN2#54 R2-062269, titled "Contention Resolution in
Non-synchronous RACH Access" (R2-062269 hereinafter) was published
as Agenda Item 11.3.4, 3GPP TSG RAN2#54, pp. 01-05 on Aug. 28-Sep.
1, 2006. cited by examiner .
3GPP TSG 22.368 (Mar. 2010), titled, "Service requirements for
Machine-Type Communications (MTC); Stage 1" (Release 10) was
published Mar. 2010. cited by examiner .
3GPP TS 36.212 V8.8.0 (Sep. 2011), titled 3rd Generation
Partnership Project; Technical Specification Group Radio Access
Network; Evolved Universal Terrestrial Radio Access (E-UTRA);
Multiplexing and channel coding (Release 8) was published Dec.
2009. cited by examiner .
3GPP TS 36.321 V9.1.0 (Dec. 2009), titled 3rd Generation
Partnership Project; Technical Specification Group Radio Access
Network; Evolved Universal Terrestrial Radio Access (E-UTRA);
Medium Access Control (MAC) protocol specification (Release 9).
cited by examiner .
3GPP TS 36.321 V9.1.0 (Dec. 2009), titled "3rd Generation
Partnership Project; Technical Specification Group Radio Access
Network; Evolved Universal Terrestrial Radio Access (E-UTRA);
Medium Access Control (MAC) protocol specification (Release 9)",
(TS 36.321 hereinafter) was published Dec. 2009, pp. 01-48. cited
by examiner .
3GPP TS 36.212 V8.8.0 (Sep. 2011), titled 3rd Generation
Partnership Project; Technical Specification Group Radio Access
Network; Evolved Universal Terrestrial Radio Access (E-UTRA);
Multiplexing and channel coding (Release 8) was published Dec.
2009. 3GPP TS 36.212 V8.8.0 (Dec. 2009). cited by examiner .
3rd Generation Partnership Project. "Contention Resolution in
Non-synchronous RACH Access." RAN2#54 , R2-062269, Aug. 28-Sep. 1,
2006, pp. 1-5, Tallinn, Estonia. cited by applicant .
3rd Generation Partnership Project. "UE Identity Validity for
connection message in RA Procedure." 3GPP TSG-RAN WG2 #59,
R2-073112, Aug. 20-24, 2007, pp. 1-2, Athens, Greece. cited by
applicant .
3rd Generation Partnership Project. 3GPP TS 22.368 V1.0.0 (Aug.
2009). 3rd Generation Partnership Project; Technical Specification
Group Services and System Aspects; Service requirements for
machine-type communications; Stage 1 (Release 10), Aug. 2009, pp.
1-22. cited by applicant .
3rd Generation Partnership Project. 3GPP TS 36.212 V8.7.0 (May
2009). 3rd Generation Partnership Project; Technical Specification
Group Radio Access Network; Evolved Universal Terrestrial Radio
Access (E-UTRA); Multiplexing and channel coding (Release 8), May
2009, pp. 1-60. cited by applicant .
3rd Generation Partnership Project. 3GPP TS 36.321 V8.5.0 (Mar.
2009). 3rd Generation Partnership Project; Technical Specification
Group Radio Access Network; Evolved Universal Terrestrial Radio
Access (E-UTRA) Medium Access Control (MAC) protocol specification
(Release 8), Mar. 2009, pp. 1-46. cited by applicant .
3rd Generation Partnership Project. "New SI proposal: RAN
Improvements for Machine-type Communications." 3GPP TSG-RAN #45,
RP-090991, Sep. 15-18, 2009, pp. 1-5, Sevilla, Spain. cited by
applicant.
|
Primary Examiner: Lai; Andrew
Assistant Examiner: Andrews, III; Hoyet H
Attorney, Agent or Firm: Murphy, Bilak & Homiller,
PLLC
Claims
The invention claimed is:
1. A method in a radio network node for sharing of a first Cell
Radio Network Temporary Identifier (C-RNTI) between at least a
first and a second communication device, wherein a radio
communication system comprises the radio network node and the first
and second communication devices, the method comprising: receiving
a first random access preamble from the first communication device;
associating the first C-RNTI to the first communication device, in
response to the first random access preamble; receiving a second
random access preamble from the second communication device; and
associating the first C-RNTI to the second communication device, in
response to the second random access preamble, while maintaining
the association of the first C-RNTI to the first communication
device, thereby sharing the first C-RNTI between said first and
second communication devices.
2. The method of claim 1, wherein associating the first C-RNTI to
the first communication device comprises assigning the first C-RNTI
to the first communication device and associating the first C-RNTI
to the second communication device comprises assigning the first
C-RNTI to the second communication device while maintaining the
assignment of the first C-RNTI to the first communication device,
wherein the first and second communication devices are connected to
the radio network node.
3. The method of claim 2, wherein the first and second
communication devices are associated to a first long identifier and
a second long identifier, respectively, wherein the first long
identifier is different from the second long identifier, the method
further comprising: receiving a third and a fourth random access
preamble, indicative of requests for sending data, from the first
and second communication devices, respectively; sending, to the
first and second communication devices, a random access response
message in response to the third and fourth random access
preambles; receiving, from the first communication device, a first
message including the first long identifier in response to the
random access response message; receiving, from the second
communication device, a second message including the second long
identifier, in response to the random access response message; and
sending, to the first and second communication devices, a
contention resolution message, comprising the first long
identifier, thereby allowing the first communication device to send
data.
4. The method of claim 2, further comprising assigning a third and
a fourth random access preamble to the first and second
communication devices, respectively, wherein the third random
access preamble is different from the fourth random access
preamble; receiving the third and fourth random access preambles,
indicative of requests for sending data, from the first and second
communication devices, respectively; sending, to the first
communication device, a random access response message including
the third random access preamble, in response the third random
access preamble; receiving, from the first communication device, a
first message including the first C-RNTI, in response to the random
access response message; and sending, to the first communication
device, a contention resolution message, comprising the first
C-RNTI, thereby allowing the first communication device to send
data.
5. The method of claim 4, wherein the radio communication system
further comprises a third communication device, wherein the method
further comprises: receiving a fifth random access preamble from
the third communication device; assigning a second C-RNTI to the
third communication device; and assigning the third random access
preamble to the third communication device, whereby the third
random access preamble is assigned to the first and third
communication devices, wherein the random access response message
including the third random access preamble further is sent to the
third communication device, the method further comprising:
receiving, from the third communication device, a second message
including the second C-RNTI, in response to the random access
response message; and further sending the contention resolution
message comprising the first C-RNTI to the third communication
device, thereby disallowing the third communication device to send
data.
6. The method of claim 1, further comprising associating a second
C-RNTI to the second communication device, whereby a group of
C-RNTIs, comprising the first and second C-RNTIs, are associated to
the second communication device.
7. The method of claim 6, wherein the first and second
communication devices are associated to a first and second long
identifier, respectively, wherein the first long identifier is
different from the second long identifier, the method further
comprising: receiving a third and a fourth random access preamble,
indicative of requests for sending data, from the first and second
communication devices, respectively; sending, to the first and
second communication devices, a random access response message in
response to the third and fourth random access preambles;
receiving, from the first communication device, a first message
including the first long identifier in response to the random
access response message; receiving, from the second communication
device, a second message including the second long identifier, in
response to the random access response message; sending, to the
first communication device, a first contention resolution message,
comprising the first C-RNTI, which is to be assigned to the first
communication device, and the first long identifier, which
indicates to the first communication device that it is allowed to
send data; and sending, to the second communication device, a
second contention resolution message, comprising the second C-RNTI,
which is to be assigned to the second communication device, and the
second long identifier, which indicates to the second communication
device that it is allowed to send data.
8. The method of claim 1, wherein the first and second
communication devices are associated to a first and a second long
identifier, respectively, wherein the first long identifier is
different from the second long identifier, further comprising:
assigning a multi-user-C-RNTI to the first and second communication
devices; sending, to the first and second communication devices, a
downlink message, including the multi-user-C-RNTI assigned to the
first or second communication device and the first long identifier,
thereby indicating to the first communication device that the
downlink message was intended to it.
9. The method of claim 8, wherein the multi-user-C-RNTI comprises
P-RNTI.
10. The method of claim 1, further comprising configuring a timer
for the first and second communication devices, respectively,
wherein the timer is indicative of when the communication device is
obliged to refrain from using the C-RNTI.
11. An arrangement in a radio network node for sharing of a first
Cell Radio Network Temporary Identifier (C-RNTI) between a first
and a second communication device, wherein a radio communication
system comprises the radio network node and the first and second
communication devices, the arrangement comprising a receiving unit
configured to receive a first random access preamble from the first
communication device, a processing circuit configured to associate
the first C-RNTI to the first communication device, in response to
the first random access preamble, wherein the receiving unit is
further configured to receive a second random access preamble from
the second communication device, and the processing circuit is
further configured to associate the first C-RNTI to the second
communication device, in response to the second random access
preamble, while the association of the first C-RNTI to the first
communication device is maintained, whereby the first C-RNTI is
shared between said first and second communication devices.
12. A method in a first communication device for enabling sharing
of a first Cell Radio Network Temporary Identifier (C-RNTI) between
at least the first communication device and a second communication
device, wherein a radio communication system comprises a radio
network node and the first and second communication devices,
wherein the first C-RNTI is assigned to the first and second
communication devices, wherein the first and second communication
devices are associated to a first and second long identifier,
respectively, wherein the first long identifier is different from
the second long identifier, the method comprising: sending a third
random access preamble, indicative of a request for sending data,
to the radio network node; receiving, from the radio network node,
a random access response message in response to the third random
access preambles; sending, to the radio network node, a first
message including the first long identifier in response to the
random access response message; receiving, from the radio network
node, a contention resolution message, comprising the first long
identifier; and checking whether the received long identifier,
comprised in the contention resolution message, is equal to the
first long identifier assigned to the first communication
device.
13. An arrangement in a first communication device for enabling
sharing of a first Cell Radio Network Temporary Identifier (C-RNTI)
between at least the first communication device and a second
communication device, wherein a radio communication system
comprises a radio network node and the first and second
communication devices, wherein the first C-RNTI is assigned to the
first and second communication devices, wherein the first and
second communication devices are associated to a first and second
long identifier, respectively, wherein the first long identifier is
different from the second long identifier, the arrangement
comprising: a sending unit configured to send a third random access
preamble, indicative of a request for sending data, to the radio
network node; a receiving unit configured to receive, from the
radio network node, a random access response message in response to
the third random access preambles; wherein the sending unit further
is configured to send, to the radio network node, a first message
including the first long identifier in response to the random
access response message; and the receiving unit further is
configured to receive, from the radio network node, a contention
resolution message, comprising the first long identifier; and a
processing circuit configured to check whether the received long
identifier, comprised in the contention resolution message, is
equal to the first long identifier assigned to the first
communication device.
Description
TECHNICAL FIELD
The present disclosure relates to a method and an arrangement in a
radio network node for sharing of a first Cell Radio Network
Temporary Identifier between at least a first and a second
communication device. Furthermore, the present disclosure relates
to a method and an arrangement in a first communication device for
enabling sharing of a first Cell Radio Network Temporary
Identifier.
BACKGROUND
In recent years, it has become more and more common to use cellular
radio communication systems for automatic exchange of information
between devices for performing many different tasks, such as
opening and closing of valves in for example a sewage system,
measuring of temperature or pressure, updating of map information
for a GPS-system in a car and more. This kind of automated
communication, without user interaction, is often referred to as
machine-to-machine (M2M) communication. As more and more devices,
such as laptops, digital cameras, cars, outdoor thermometers,
indoor thermometers, electricity meters and so on, become
connected, the number of connections in the radio communication
systems will increase drastically.
In Third Generation Partnership Project Long Term Evolution (3GPP
LTE), all scheduling assignments, grants and commands are issued to
specific Radio Network Temporary Identifiers (RNTI). The RNTI is a
number between 0 and 2.sup.16. Different types of RNTIs exist, such
as the Paging RNTI (P-RNTI), System Information RNTI (SI-RNTI),
etc. For example, a communication device (or user equipment, "UE")
that is reading e.g. System Information is looking for the commands
assigned to the SI-RNTI on the Physical Downlink Control Channel
(PDCCH). RNTIs can either be common to several communication
devices, or unique to one specific communication device.
Specifically, the Cell RNTI (C-RNTI) is used to address a specific
communication device in a connected state, such as RRC CONNECTED
state in case of an LTE system. A communication device in RRC
CONNECTED state has established a connection to a cellular radio
communication network. Therefore, the communication device in RRC
CONNECTED state needs at least one C-RNTI that is unique among the
C-RNTIs assigned to other communication devices in RRC CONNECTED
state in the same cell. Multiple RNTIs may be allocated to a
communication device at the same time, i.e. in parallel. For
example, a Semi-Persistent Scheduling RNTI (SPS-RNTI) may be
assigned to a communication device in addition to the
aforementioned C-RNTI.
The RNTIs in current LTE network are signalled by 16 bits, meaning
that 2.sup.16=65 536 values are possible. However, in practice, it
can be speculated that if allocations of RNTIs are very closely in
the RNTI space (in terms of the Hamming distance), this would lead
to a high probability of RNTI misdetection. If this is the case, it
is possible that only a fraction of the current RNTI number space
can be utilized in practice.
The following problems make the C-RNTI values limited: all RRC
connections need at least one RNTI, i.e. the C-RNTI, only one
connection can be identified with one C-RNTI, and some connections
may require multiple RNTIs.
Furthermore, as explained above, not all RNTI values are available
for C-RNTI use, but only a subset (albeit a large one) is actually
allocated for C-RNTIs.
In the following example, scheduling of a communication device on
PDCCH (Physical Downlink Control Channel) using a C-RNTI as
specified by 3GPP LTE is described. PDCCH is used for carrying e.g.
downlink scheduling assignments and uplink scheduling grants. The
assignments and grants include detailed information of PDSCH/PUSCH
(Physical Downlink Shared Channel/Physical Uplink Shared Channel)
resource indication, transport format, hybrid-ARQ (Automatic Repeat
reQuest) information etc. A Cyclic Redundancy check (CRC) is
attached to PDCCH payload, where the RNTI is included in CRC
calculation. Upon on reception of PDCCH, the communication device
will check the CRC using its unique C-RNTI. If the CRC matches, the
communication device may conclude that the message is intended to
it.
Consider the following scenario. It is assumed that data becomes
available for transmission in the communication device, but the
communication device does not have UL resources to transmit the
data, even when the communication device is in the RRC CONNECTED
state. Thus, the communication device requests resources with a
Scheduling Request (SR) from a radio network node, such as an eNB.
Then, the SR initiates a Random Access (RA) procedure if Physical
Uplink Control Channel (PUCCH) resources are not allocated for
transmission of the SR. In a contention based RA, the communication
device selects a random preamble to be transmitted in Random Access
Channel (RACH). For this case, the RA procedure is as follow: The
communication device transmits a random preamble selected by it on
RACH (as noted above). The radio network node responds with a RA
Response (RAR) for the same preamble as transmitted by the
communication device. RAR message includes a Scheduling Grant (SG)
for an uplink transmission. The communication device now responds
to the RAR with a scheduled message 3 (as known from
3GPP-terminology) including a C-RNTI thus identifying the
communication device. The radio network node then replies with a
Contention Resolution message. If the Contention Resolution message
includes the same C-RNTI as the communication device has
transmitted in message 3, the communication device regards the
Random Access Procedure as successful.
The above described method is contention based, because two
communication devices can request resources at the same time with
the same preamble. In this case the radio network indicates by
means of C-RNTI in Contention Resolution message which of the
communication device succeeds with the random access.
The Discontinuous Reception (DRX) procedure, defined as a part of
the LTE Medium Access Control (MAC), specifies time periods during
which a communication device is obliged to monitor the PDCCH. In
DRX, an active time is defined for this purpose. In time periods,
specified as active time, the communication device is not allowed
to go to a sleep state, which consumes less power. Active time is
calculated based on specific DRX timers and cycles in such a way
that the network and the communication device have a similar
understanding of when it is possible to schedule the communication
device.
Some devices may transmit so called keep-alive messages just to
avoid loss of the connection to avoid switching between connected
and idle state. From a communication device perspective, it is
beneficial to be connected continuously since data may be
transmitted and received fast when needed (no time is wasted on
setting up a connection). Furthermore, the network settings and the
traffic generated at the communication device may cause the
communication device to always stay connected even if the
connection is only needed for short periods at a time. Hence, a
C-RNTI may be occupied for long periods of time even if the
communication device does not transmit a lot of information.
As the number of connections, due to for example automated
communication from communication devices in the radio networks
increases, it is possible that the current number of usable RNTI
values is not enough to cater for all the devices in the network
simultaneously. An example where this may happen is a dense sensor
network including a huge amount of temperature/pressure/humidity
sensors. In addition, there may be user equipments, such as
cellular phones, in the same cell as the sensors. These user
equipments may also be connected and, hence, consume (or occupy) a
C-RNTI. A solution according to prior art is such that each
communication device, i.e. sensor or user equipment, has its own
connection to the network. Thus, each communication device requires
a C-RNTI that is unique in the cell.
Next, a numerical example of the RNTI limitation is described.
Consider X devices, such as weather sensors located in a cell. Each
communication device is in RRC CONNECTED state, thereby a unique
C-RNTI for each communication device is required. Each
communication device sends a measurement report once in every 10
seconds. The size of the measurement report is 1000 bits. Thus, the
traffic load generated by each device is: r=1000 bit/10 s=100
bps.
The aggregate traffic generated by X devices is r*X. Assume that
the cell throughput of a typical LTE cell is 10 Mbps. From the
system capacity point of view, it is possible to have X=10 Mbps/100
bps=100 000 devices in a cell.
Therefore, since the RNTI space is limited to 16 bits (which yields
65 536 possible RNTI values), a problem of prior art solutions is
that the number of RNTIs does not suffice.
When the RNTI space is exhausted, the network needs to drop
connections of some devices to allow for other devices to connect
instead. Switching frequently between connected and idle state
increases amount of signalling messages, overhead and also battery
consumption. For small devices having only very limited battery,
this is not desirable.
SUMMARY
An object may be to enable large amounts of communication devices
to be connected to a radio network node.
According to an aspect, the object may be achieved by a method in a
radio network node for sharing of a first Cell Radio Network
Temporary Identifier, referred to as "C-RNTI" between at least a
first and a second communication device. A radio communication
system comprises the radio network node and the first and second
communication devices. The radio network node receives a first
random access preamble from the first communication device.
Furthermore, the radio network node associates the first C-RNTI to
the first communication device, in response to the first random
access preamble. The radio network node receives a second random
access preamble from the second communication device. Moreover, the
radio network node associates the first C-RNTI to the second
communication device, in response to the second random access
preamble, while the association of the first C-RNTI to the first
communication device is maintained. In this manner, the first
C-RNTI is shared between said first and second communication
devices.
According to another aspect, the object may be achieved by an
arrangement in a radio network node for sharing of a first Cell
Radio Network Temporary Identifier, referred to as "C-RNTI",
between a first and a second communication device. A radio
communication system comprises the radio network node and the first
and second communication devices. The arrangement may comprise a
receiving unit configured to receive a first random access preamble
from the first communication device, and a processing circuit
configured to associate the first C-RNTI to the first communication
device, in response to the first random access preamble. The
receiving unit may further be configured to receive a second random
access preamble from the second communication device. The
processing circuit may further be configured to associate the first
C-RNTI to the second communication device, in response to the
second random access preamble, while the association of the first
C-RNTI to the first communication device is maintained. In this
manner, the first C-RNTI is shared between said first and second
communication devices.
In some embodiments of the present invention, the C-RNTI is
associated to the second UE, while the association of the C-RNTI to
the first UE is maintained. In this manner, the C-RNTI is shared
between the first and second communication devices. As a result,
large amounts of communication devices may be connected to the
radio network node. Hence, in order to alleviate the problem of the
fact that the number of C-RNTIs may not suffice for predicted
future scenarios where huge amounts of communication devices are
connected to a radio network node, the present inventors have
realized that it may be beneficial to present a solution that
allows sharing of at least one C-RNTI between at least two
communication devices in a connected state, such as RRC CONNECTED
state.
An advantage is that a limited number of C-RNTIs, as defined by
current specifications, may be used by a larger number of
communication devices as compared to prior art solutions. Hence,
without increasing the number of usable C-RNTIs, the present
solution enables large amounts of communication devices to be
connected to the radio network node.
In some embodiments, the association of the first C-RNTI to the
first communication device comprises assigning the first C-RNTI to
the first communication device. Furthermore, the association of the
first C-RNTI to the second communication device comprises assigning
the first C-RNTI to the second communication device, while
maintaining the assignment of the first C-RNTI to the first
communication device. In some embodiments, the first and second
communication devices are connected to the radio network node.
In some embodiments, the first and second communication devices are
associated to a first and second long identifier, respectively. The
first long identifier is different from the second long identifier.
The radio network node receives a third and a fourth random access
preamble, indicative of requests for sending data, from the first
and second communication devices, respectively. The radio network
node sends, to the first and second communication devices, a random
access response message in response to the third and fourth random
access preambles. The radio network node receives, from the first
communication device, a first message including the first long
identifier in response to the random access response message. The
radio network node receives, from the second communication device,
a second message including the second long identifier, in response
to the random access response message. The radio network node
sends, to the first and second communication devices, a contention
resolution message, comprising the first long identifier, thereby
allowing the first communication device to send data.
In some embodiments, the following steps may be performed. The
radio network node assigns a third and a fourth random access
preamble to the first and second communication devices,
respectively. The third random access preamble is different from
the fourth random access preamble. The radio network node receives
the third and fourth random access preambles, indicative of
requests for sending data, from the first and second communication
devices, respectively. The radio network node sends, to the first
communication device, a random access response message including
the third random access preamble, in response to the third random
access preamble. The radio network node receives, from the first
communication device, a first message including the first C-RNTI,
in response to the random access response message. The radio
network node sends, to the first communication device, a contention
resolution message, comprising the first C-RNTI assigned to the
first communication device, which enables the first communication
device to determine whether it is allowed or not allowed to send
data.
In some embodiments, the radio communication system further
comprises a third communication device. The radio network node
receives a fifth random access preamble from the third
communication device. The radio network node assigns a second
C-RNTI to the third communication device. The radio network node
assigns the third random access preamble to the third communication
device. Moreover, the random access response message including the
third random access preamble is further sent to the third
communication device. The radio network node receives, from the
third communication device, a second message including the second
C-RNTI, in response to the random access response message. Further,
the contention resolution message, comprising the first C-RNTI is
sent to the third communication device, thereby disallowing the
third communication device to send data.
In some embodiments, the first and second communication devices are
associated to a first and second long identifier, respectively. The
first long identifier is different from the second long identifier.
The radio network node receives a third and fourth random access
preamble, indicative of requests for sending data, from the first
and second communication devices, respectively. The radio network
node sends, to the first and second communication devices, a random
access response message in response to the third and fourth random
access preambles. The radio network node receives, from the first
communication device, a first message including the first long
identifier in response to the random access response message. The
radio network node receives, from the second communication device,
a second message including the second long identifier, in response
to the random access response message. The radio network node
sends, to the first communication device, a first contention
resolution message, comprising the first C-RNTI, which is to be
assigned to the first communication device, and the first long
identifier, which indicates to the first communication device that
it is allowed to send data. The radio network node sends, to the
second communication device, a second contention resolution
message, comprising the second C-RNTI, which is to be assigned to
the second communication device, and the second long identifier,
which indicates to the second communication device that it is
allowed to send data.
In some embodiments, the first and second communication devices are
associated to a first and a second long identifier, respectively.
The first long identifier is different from the second long
identifier. The radio network node assigns (or associates in some
embodiments) a multi-user-C-RNTI (MC-RNTI) to the first and second
communication devices. The radio network node selects one of the
first and second communication devices, to be allowed to receive
data (i.e. to which selected communication device the data is
intended). The radio network node sends a downlink message,
including the multi-user-C-RNTI and the first long identifier, to
the first and second communication devices. The first long
identifier enables each of the first and second communication
devices, to determine whether the downlink message was intended to
it.
In some embodiments, the radio network node configures a timer for
the first and second communication devices, respectively, wherein
the timer is indicative of when the communication device, is
obliged to refrain from using the C-RNTI.
According to yet another aspect, the object may be achieved by a
method in a first communication device for enabling sharing of a
first Cell Radio Network Temporary Identifier, referred to as
"C-RNTI" between at least the first communication device and a
second communication device. A radio communication system comprises
a radio network node and the first and second communication
devices. The first C-RNTI is assigned to the first and second
communication devices. The first and second communication devices
are associated to a first and second long identifier, respectively.
The first long identifier is different from the second long
identifier. The first communication device sends a third random
access preamble, indicative of a request for sending data, to the
radio network node. The first communication device receives, from
the radio network node, a random access response message in
response to the third random access preambles. The first
communication device sends, to the radio network node, a first
message including the first long identifier in response to the
random access response message. The first communication device
receives, from the radio network node, a contention resolution
message, comprising the first long identifier. The first
communication device checks whether the received long identifier,
comprised in the contention resolution message, is equal to the
first long identifier assigned to the first communication
device.
According to a further aspect, the object may be achieved by an
arrangement in a first communication device for enabling sharing of
a first Cell Radio Network Temporary Identifier, referred to as
"C-RNTI" between at least the first communication device and a
second communication device. A radio communication system comprises
a radio network node and the first and second communication
devices. The first C-RNTI is assigned to the first and second
communication devices. The first and second communication devices
are associated to a first and second long identifier, respectively.
The first long identifier is different from the second long
identifier. The arrangement may comprise a sending unit configured
to send a third random access preamble, indicative of a request for
sending data, to the radio network node. The arrangement further
comprises a receiving unit configured to receive, from the radio
network node, a random access response message in response to the
third random access preamble. The receiving unit may be a receiver.
Moreover, the sending unit is further configured to send, to the
radio network node, a first message including the first long
identifier in response to the random access response message, and
the receiving unit is further configured to receive, from the radio
network node, a contention resolution message, comprising the first
long identifier. Furthermore, the arrangement comprises a
processing circuit configured to check whether the received long
identifier, comprised in the contention resolution message, is
equal to the first long identifier assigned to the first
communication device.
In some embodiments, the first communication device sends, to the
radio network node, a first message including the first long
identifier in response to the random access response message and
checks whether the received long identifier, comprised in the
contention resolution message, is equal to the first long
identifier assigned to the first communication device. In this
manner, the first communication device makes it possible for the
radio network node to distinguish the first and second
communication devices from each other by means of including, for
example, the first long identifier (if the first communication
device is chosen for transmission) in the contention resolution
message. Moreover, the first communication device may be aware of
whether it is allowed or not allowed to use the first C-RNTI, since
the first communication device may have checked the long identifier
comprised in the contention resolution message to determine whether
it is allowed or not allowed to send data.
Further features of, and advantages with, embodiments of the
present invention will become apparent when studying the appended
claims and the following description. Those skilled in the art
realize that different features of the embodiments may be combined
to create embodiments other than those described in the following,
without departing from the scope of the present invention, as
defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The various aspects of embodiments of the present invention,
including its particular features and advantages, will be readily
understood from the following detailed description and the
accompanying drawings, in which:
FIG. 1 shows a schematic overview of an exemplifying radio
communication system, in which embodiments of the present invention
may be implemented,
FIG. 2 shows a schematic, combined signalling and flow chart of an
embodiment of a method in the radio communication system according
to FIG. 1 for sharing of a C-RNTI between at least a first and a
second communication device,
FIG. 3 shows a schematic, combined signalling and flow chart of
another embodiment of the method in the radio communication system
according to FIG. 1,
FIG. 4 shows a schematic, combined signalling and flow chart of
another embodiment of the method in the radio communication system
according to FIG. 1,
FIG. 5 shows a schematic, combined signalling and flow chart of
another embodiment of the method in the radio communication system
according to FIG. 1,
FIG. 6 shows a schematic, combined signalling and flow chart of
another embodiment of the method in the radio communication system
according to FIG. 1,
FIG. 7 shows a schematic, combined signalling and flow chart of
another embodiment of the method in the radio communication system
according to FIG. 1,
FIG. 8 shows a schematic block diagram of an arrangement in the
radio network node according to an embodiment of the present
invention.
FIG. 9 shows a schematic flow chart of a method in a first
communication device for enabling sharing of a first C-RNTI,
and
FIG. 10 shows a schematic, exemplifying block diagram of an
embodiment of an arrangement 900 in a first communication device
110 for enabling sharing of a first C-RNTI.
DETAILED DESCRIPTION
Throughout the following description similar reference numerals
have been used to denote similar nodes, devices, elements, parts,
items, steps or features, when applicable. In the Figures, optional
steps are indicated by dashed lines where applicable.
In FIG. 1, there is shown a schematic overview of an exemplifying
radio communication system 100, in which embodiments of the present
invention may be implemented. The radio communication system 100
may be a radio communication system, such as an LTE system, a HSPA
system, WiMAX system or the like. In some cases, the radio
communication system 100 may be based on Orthogonal Frequency
Division Multiplexing (OFDM). The radio communication system 100
comprises a first, second and third communication device 110, 120,
130 (or a UE1, UE2 and UE3 as shown in FIG. 1) and a radio network
node 140, such as an eNB in case of an LTE system. In some
embodiments, the first, second and third communication devices 110,
120, 130 may each comprise a sensor unit, comprising a transceiver
(not shown in FIG. 1) adapted for radio communication with the
radio network node 140. In cases, when the first, second and third
communication devices 110, 120, 130 each comprises a
machine-type-device, such as a laptop, a digital camera, a car, an
outdoor thermometer, an indoor thermometer, an electricity meter or
other device which may communicate (or be operated autonomously)
without input from a user, the solutions presented herein may be
particularly preferred. The arrows between the radio network node
140 and the first, second and third communication devices,
respectively, denote that a connection, such as an RRC connection,
may be established between the respective communication device and
the radio network node 140.
As used herein, the term "communication device" has been used to
denote any device capable of communicating with the radio
communication system.
As used herein the term "machine-type-device" has been used to
denote a subset of communication devices of all types. A
machine-type-device is characterized by that it may automatically
communicate with a radio communication system without any need for
user interaction. As an example, a machine-type-device may be a
temperature sensor which may send information about the temperature
at the location of the temperature sensor to the radio
communication system. Notably, the present solution is also
applicable to communication devices that are not
machine-type-devices.
As used herein the term "user equipment" has been used to denote a
subset of communication devices of all types. A user equipment may,
as an example, denote any communication device which comprises a
display for interaction with a user.
As used herein the term "associate" has been used to (1) denote
that, for example, the radio network node internally keeps track
of, for example, a C-RNTI and an associated communication device or
(2) to denote that the radio network node sends a message to the
communication device, which sets its context according to the
message. This latter meaning (2) is also referred to by the term
"assigning". Hence, the term "associate" is broader than the term
"assign". When a C-RNTI has been assigned to a communication
device, the context of the communication device is affected,
whereas when a C-RNTI has been associated to a communication
device, the context of the communication device must not be
affected, but may be affected in some cases.
In FIG. 2, there is shown a schematic, combined signalling and flow
chart of an embodiment of the method in the radio communication
system according to FIG. 1 for sharing of a C-RNTI between at least
a first and a second communication device 110, 120 (UE1, UE2). A
radio communication system 100 comprises the radio network node 140
and the first and second communication devices 110, 120. The
following steps may be performed. Notably, in some embodiments of
the method the order of the steps may differ from what is indicated
below. 210 The radio network node 140 receives a first random
access preamble from the first communication device 110. More
specifically, the first random access preamble may be sent on RACH.
220 The radio network node 140 associates the first C-RNTI to the
first communication device 110, in response to the first random
access preamble. 230 The radio network node 140 receives a second
random access preamble from the second communication device 120.
More specifically, the second random access preamble may be sent on
RACH. 240 The radio network node 140 associates the first C-RNTI to
the second communication device 120, in response to the second
random access preamble, while the association of the first C-RNTI
to the first communication device 110 is maintained. Thus, the
first C-RNTI is shared between said first and second communication
devices 110, 120. As a result, the first and second communication
device 110, 120 may be connected to the radio network node 140,
i.e. the first and second communication devices 110, 120 may be in
RRC CONNECTED state without necessarily being assigned a respective
C-RNTI as in prior art solutions.
In scenarios where tremendous amounts of communication devices are
expected, it is herein presented a solution in which the C-RNTIs
are allowed to be shared between several communication devices. In
this manner, the radio network node 140 may allow a larger number
of communication devices to be connected to it without increasing
the number of C-RNTIs. In existing solutions, it is only allowed to
assign one C-RNTI to one communication device in one cell, i.e. in
a one-to-one relationship. Disadvantages with increasing the number
of useable C-RNTIs are for example: increased overhead in scenarios
where there are comparably few connections, increased overhead may
lead to decreased capacity for data, and if the RNTI length is be
changed, the total structure of PDCCH carrying RNTIs needs to be
changed as well.
Since sharing of a C-RNTI, as introduced by embodiments of the
present invention, is allowed, problems occur in distinguishing one
communication device from another, when, for example, two or more
communication devices send scheduling requests (random access
preambles) simultaneously, and when the radio network node wishes
to send data to the communication device. These and other problems
are solved by the embodiments presented in FIGS. 3 to 7.
In some embodiments of the method in the radio network node 140,
which applies to the embodiments shown in FIGS. 3 and 4, the
association 220 of the first C-RNTI to the first communication
device 110 comprises assigning the first C-RNTI to the first
communication device 110. Furthermore, the association 240 of the
first C-RNTI to the second communication device 120 comprises
assigning the first C-RNTI to the second communication device 120,
while maintaining the assignment of the first C-RNTI to the first
communication device 110. In some embodiments, the first and second
communication devices 110, 120 are connected to the radio network
node 140. Expressed differently, the radio network node 140 assigns
the first C-RNTI to both the first and second communication devices
110, 120, when the first and second communication devices 110, 120
are connected to the radio network node 140. When the first and
second communication device 110, 120 are connected to the radio
network node 140, they may have entered, for example, RRC CONNECTED
state (as known from 3GPP-terminology). It shall, hence, be noted
that this embodiment allows the first C-RNTI to be assigned to the
first and second communication devices simultaneously.
Now referring to FIG. 3, in some embodiments of the method in the
radio network node 140, the first and second communication devices
110, 120 are associated to a first and second long identifier,
respectively. The first long identifier is different from the
second long identifier. More specifically, the first and second
long identifiers may be temporary mobile subscriber identities
(TMSI) or international mobile subscriber identities (IMSI) of the
first and/or second communication devices. In this manner, higher
layer identifiers are used by the radio network node 140 to
distinguish the first communication device 110 from the second
communication device 120. The following steps may be performed.
Notably, in some embodiments of the method the order of the steps
may differ from what is indicated below. 310 The radio network node
140 receives a third and a fourth random access preamble,
indicative of requests for sending data, from the first and second
communication devices 110, 120, respectively. As an example, the
third and fourth random access preambles may be sent by the first
and second communication devices in conjunction with a Scheduling
Request (SR) on RACH or PUCCH (Physical Uplink Control Channel).
320 The radio network node 140 sends, to the first and second
communication devices 110, 120, a random access response message in
response to the third and fourth random access preambles. More
specifically, the random access response message may include a
scheduling grant for an uplink transmission from the first and
second communication device 110, 120. Since both the first and
second communication device may not transmit according to the
scheduling grant, this conflict needs to be resolved as described
in the following steps. 330 The radio network node 140 receives,
from the first communication device 110, a first message including
the first long identifier (1st long id.) in response to the random
access response message. More specifically, the first message may
be a message 3 (as known from 3GPP-terminology) albeit somewhat
modified in that the first message comprises a long identifier,
e.g. the first long identifier, which is not present in a message 3
according to 3GPP-terminology, when the first and/or second
communication device is in connected state, such as RRC CONNECTED
state. 340 The radio network node 140 receives, from the second
communication device 120, a second message including the second
long identifier (2nd long id.), in response to the random access
response message. More specifically, the second message may be
another message 3 albeit somewhat modified. 370 The radio network
node 140 sends, to the first and second communication devices 110,
120, a contention resolution message, comprising the first long
identifier, thereby allowing the first communication device 110 to
send data. The first communication device 110 is allowed to send
data because the first long identifier, transmitted by the first
communication device 110 to the radio network earlier, is comprised
in the contention resolution message. Thereby, the radio network
node 140 has resolved the conflict by allowing only one of the
first and second communication devices 110, 120 to send (or
receive) data. It may be noted that it is the content of the
contention resolution message (i.e. the first long identifier
comprised in the contention resolution message) that allows each of
the first and second communication devices 110, 120 to determine
whether or not it is allowed to send and receive data. Expressed
differently, in the step 370, the first communication device 110
receives the contention resolution message comprising the first
long identifier. 380 This step is not comprised in the method
performed by the radio network node 140. The first communication
device 110 checks whether the received long identifier, comprised
in the contention resolution message, is equal to the long
identifier of the first communication device 110. In that case, the
first communication device 110 may use the first C-RNTI and may
consequently send data. It may be noted that the first C-RNTI is
reserved for use by the first communication device 110 from this
point onward.
The second communication device 120 may also receive the contention
resolution message as shown in FIG. 3 by an arrow in conjunction
with step 370. Then, the second communication device 120 may check
(not shown in FIG. 3) whether the received long identifier,
comprised in the contention resolution message, is equal to the
long identifier of the second communication device 120. The first
long identifier, i.e. the received long identifier, is, in this
case, not equal to the second long identifier of the second
communication device 120 and the second communication device 120
may not use the first C-RNTI. Hence, the second communication
device 120 may not send data. Furthermore, the first communication
device 110 may, after the step of 380, follow any assignments or
commands issued with the first C-RNTI. Any other communication
device, such as the second communication device 120, sharing the
first C-RNTI with the first communication device 110, may not obey
or listen to any assignments or commands issued with the first
C-RNTI. In this case, the second communication device 120 is aware
of that it may not obey or listen to any assignments or commands
issued with the first C-RNTI, because the contention resolution
message does not comprise the second long identifier associated to
the second communication device 120.
Again with reference to FIG. 3, in some embodiments of the method
in the radio network node 140, the following steps may be
performed. Notably, in some embodiments of the method the order of
the steps may differ from what is indicated below. 350 Optionally,
the radio network node 140 selects at least one of the first and
second communication devices 110, 120 to be allowed to send data.
Hence, a selected communication device may be allowed to send data.
360 Optionally, the radio network node 140 selects the first or
second long identifier based on the first or second communication
device 110, 120 according to selection in step 350. Hence, a
selected long identifier is based on the selected communication
device.
When steps 350 and 360 have been performed, the contention
resolution message of the step 380 comprises the selected long
identifier, i.e. the first or second long identifier.
In some embodiments, before the sending of the contention
resolution message, the contention resolution message is generated
based on which of the first and second communication device shall
be allowed to send data. E.g. the first long identifier is
comprised in the contention resolution message when it is desired
that the first communication device 110 shall be allowed to send
data and the second long identifier is comprised in the contention
resolution message when it is desired that the second communication
device 120 shall be allowed to send data. When generating the
contention resolution message different considerations may be taken
into account. For example, the communication device to be allowed
to send data may be set arbitrarily, be selected based on type of
data that the communication device intends to send (as an example,
voice data may have higher priority than infrequency reported
measurement data), or be selected based on the type of the
communication device, such as machine-type-device or user
equipment.
With reference to FIG. 4, in a further embodiment of the method in
the radio network node 140, the following steps may be performed.
Here the steps related to the first and second communication
devices 110, 120 are described. The steps related to a third
communication device 130, shown in FIG. 4, are described in the
next paragraph. Notably, in some embodiments of the method the
order of the steps may differ from what is indicated below. 410 The
radio network node 140 assigns a third and a fourth random access
preamble to the first and second communication devices 110, 120,
respectively. The third random access preamble is different from
the fourth random access preamble. By means of the third and fourth
random access preambles, the radio network node 140 may now
designate a message to the first communication device 110 or the
second communication device 120. In some embodiments, the third
random access preamble may be assigned to a group of communication
devices. Different C-RNTIs are assigned to each of the
communication devices in the group. 420 The radio network node 140
receives the third and fourth random access preambles, indicative
of requests for sending data, from the first and second
communication devices 110, 120, respectively. As an example, the
third and fourth random access preambles may be sent by the first
and second communication devices in conjunction with a Scheduling
Request (SR) on RACH or PUCCH (Physical Uplink Control Channel).
450 The radio network node 140 sends, to the first communication
device 110, a random access response message including the third
random access preamble, in response to the third random access
preamble. The second communication device 120 is assigned to the
fourth random access preamble and is hence not, figuratively
speaking, receiving the random access response message. 460 The
radio network node 140 receives, from the first communication
device 110, a first message including the first C-RNTI, in response
to the random access response message. More specifically, the first
message may be a first message 3. 470 The radio network node 140
sends, to the first communication device 110, a contention
resolution message, comprising the first C-RNTI assigned to the
first communication device 110, which enables the first
communication device 110 to determine whether it is allowed or not
allowed to send data. 480 The first communication device 110 has
received the contention resolution message comprising the first
C-RNTI. The first communication device 110 checks whether the first
C-RNTI is assigned to the first communication device 110. If the
first C-RNTI is assigned to the first communication device 110, the
first communication device 110 may use the first C-RNTI. In this
example, the first communication device 110 may send data (random
access was successful). The first C-RNTI is reserved for use by the
first communication device 110 from this point onward.
Furthermore, also with reference to FIG. 4, in some embodiments of
the method in the radio network node 140, the radio communication
system 100 further comprises a third communication device 130. The
following steps, relating to the third communication device 130,
may be performed. Notably, in some embodiments of the method the
order of the steps may differ from what is indicated below. 250 The
radio network node 140 receives a fifth random access preamble from
the third communication device 130. More specifically, the firth
random access preamble may be received on RACH. 260 The radio
network node 140 assigns a second C-RNTI to the third communication
device 130. 410 The radio network node 140 assigns the third random
access preamble to the third communication device 130. Thus, the
third random access preamble is assigned to the first and third
communication devices 110, 130.
Moreover, the random access response message including the third
random access preamble further sent to the third communication
device 130, i.e. the random access response message of step 450
above is also received by the third communication device 130. The
random access response message may be received by the third
communication device because the third random access preamble is
assigned to the third communication device 130. 465 The radio
network node 140 receives, from the third communication device 130,
a second message including the second C-RNTI, in response to the
random access response message. More specifically, the second
message may be a second message 3.
Further, the contention resolution message, comprising the first
C-RNTI is sent to the third communication device 130, thereby
disallowing the third communication device 130 to send data. That
is to say, the contention resolution message of step 470 above is
also received by the third communication device 130. The third
communication device 130 will not be allowed to send data, since
the second C-RNTI, not the first C-RNTI, has been assigned to the
third communication device. Again, but expressed differently, in
conjunction with step 485 below. 485 The third communication device
130 receives the contention resolution message comprising the first
C-RNTI. The third communication device 130 checks whether the first
C-RNTI is assigned to the third communication device 130. In this
example, the first C-RNTI has not been assigned to the third
communication device 130, but instead the second C-RNTI has been
assigned to the third communication device 130. Hence, the third
communication device 130 may not send data.
In some embodiments of the method in the radio network node 140,
the optional steps indicated in FIG. 4 may be performed. Notably,
in some embodiments of the method the order of the steps may differ
from what is indicated below. 430 Optionally, the radio network
node 140 selects one of the first and second communication devices
110, 120 to be allowed to send data. Thus, a selected communication
device may be allowed to send data. 440 Optionally, the radio
network node 140 selects the third or fourth random access preamble
based on the first or second communication device 110, 120
according to selection in step 430. A selected random access
preamble may be one of the third and fourth random access
preambles. Here, the third random access preamble may be the
selected random access preamble in order to match the random access
preamble assigned to the first communication device 110.
In FIG. 5, there is illustrated another embodiment of the method in
the radio network node 140, in which a pool of C-RNTIs is
associated to the second communication device 120. It may be noted
that, even though the second communication device 120 may be in RRC
CONNECTED state, a C-RNTI has not been assigned to the second
communication device 120. Instead, the pool of C-RNTIs is
associated to the second communication device 120. Thanks to the
pool of C-RNTIs, being associated to the second communication
device 120, it is be possible to select a C-RNTI to be used by the
second communication device 120, which selected C-RNTI is not used
by the first communication device 110. Thereby, it is possible for
both the first and second communication device 110, 120 to send
data, even though there initially appeared to be a conflict.
In some embodiments of the method in the radio network node 140, as
shown in FIG. 5, the following step may be performed. 245 The radio
network node 140 associates a second C-RNTI to the second
communication device 120, whereby a group of C-RNTIs, comprising
the first and second C-RNTIs, are associated to the second
communication device 120.
In some embodiments of the method in the radio network node 140,
also illustrated in FIG. 5, the first and second communication
devices 110, 120 are associated to a first and second long
identifier, respectively. The first long identifier is different
from the second long identifier. The following steps may be
performed. Notably, in some embodiments of the method the order of
the steps may differ from what is indicated below. 310 The radio
network node 140 receives a third and fourth random access
preamble, indicative of requests for sending data, from the first
and second communication devices 110, 120, respectively. 320 The
radio network node 140 sends, to the first and second communication
devices 110, 120, a random access response message in response to
the third and fourth random access preambles. More specifically,
the random access response message may include a scheduling grant
for an uplink transmission from the first and second communication
device 110, 120. Thanks to the pool of C-RNTIs associated to the
second communication device 120, it shall be seen from the
following steps that both the first and second communication
devices 110, 120 may transmit while listening to commands or
assignments issued with the first and second C-RNTI, respectively.
330 The radio network node 140 receives, from the first
communication device 110, a first message including the first long
identifier (1st long id.) in response to the random access response
message. More specifically, the first message may be a first
message 3, albeit somewhat modified. 340 The radio network node 140
receives, from the second communication device 120, a second
message including the second long identifier (2nd long id.), in
response to the random access response message. More specifically,
the second message may be a second message 3 albeit somewhat
modified. 370 The radio network node 140 sends, to the first
communication device 110, a first contention resolution message,
comprising the first C-RNTI, which is to be assigned to the first
communication device 110, and the first long identifier, which
indicates to the first communication device 110 that it is allowed
to send data. Expressed differently, the first communication device
110 receives the first contention resolution message, comprising
the first long identifier. The first long identifier is indicative
of whether the first communication device 110 is allowed or not
allowed to send (and receive) data. 375 The radio network node 140
sends, to the second communication device 120, a second contention
resolution message, comprising the second C-RNTI, which is to be
assigned to the second communication device 120, and the second
long identifier, which indicates to the second communication device
120 that it is allowed to send data. Expressed differently, the
second communication device 120 receives the second contention
resolution message, comprising the second long identifier.
When the radio network node 140 creates the first and second
contention resolution messages above, the radio network node 140
needs to ensure that the C-RNTIs of the first and second contention
resolution messages are different (as exemplified above). 380 When
checking whether the long identifier comprised in the received
contention resolution message is equal to the long identifier of
the first communication device 110, the first communication device
110 will find that those long identifiers are equal. Hence, the
first communication device 110 may use the first C-RNTI and send
data. In this example, the second communication device 120 will
find that the received long identifier, comprised in the second
contention resolution message, is equal to the second long
identifier of to the second communication device 120. Thus, the
second communication device 120 may send data, using the second
C-RNTI comprised in the second contention resolution message. Thus,
the first C-RNTI is reserved for use by the first communication
device 110 and the second C-RNTI is reserved for use by the second
communication device 120 from this point onward.
As a result, both the first and second communication devices 110,
120 may send data using different C-RNTIs, i.e. the first and
second C-RNTI, which from this point onward are reserved for use by
the first and second communication devices 110, 120,
respectively.
Another problem occurs in scenarios where the first and second
communication devices 110, 120 may receive data in the downlink
prior to sending data in the uplink. Normally, such communication
device may be reached by forcing the device to resynchronize with
the radio network node 140 through a PDCCH order to the C-RNTI of
the communication device. With the present solution, further steps
need to be taken in order to distinguish multiple communication
devices, such as the first and second communication devices, being
assigned or associated to the same C-RNTI, such as the first
C-RNTI.
Now referring to FIG. 6, there is illustrated a scenario in which
the radio network node 140 initiates communication with the
communication devices 110, 120. The first and second communication
devices 110, 120 are associated to a first and a second long
identifier, respectively. The first long identifier is different
from the second long identifier. More specifically, the first and
second long identifiers may be temporary mobile subscriber
identities (TMSI) or international mobile subscriber identities
(IMSI) of the first and/or second communication devices. In this
manner, higher layer identifiers are used by the radio network node
140 to distinguish the first communication device 110 from the
second communication device 120. The following steps may be
performed. Notably, in some embodiments of the method the order of
the steps may differ from what is indicated below. 610 The radio
network node 140 assigns (or associates in some embodiments) a
multi-user-C-RNTI (MC-RNTI) to the first and second communication
devices 110, 120. For example, all communication devices assigned
with the C-RNTI values "45" and "78" listen to the MC-RNTI value
"4", and all communication devices sharing the C-RNTI value "678"
listen to commands assigned using the MC-RNTI value "5". Thus, the
MC-RNTI operates as a "paging" RNTI, where multiple communication
devices are reached with the same identity, but where only the
message content reveals who the message is intended for. One
specific embodiment is thus to use the P-RNTI (i.e. MC-RNTI is
"replaced" by the existing P-RNTI) and the paging channel (PCH) to
reach UEs in RRC CONNECTED, when such communication devices share
identities. 620 The radio network node 140 selects one of the first
and second communication devices 110, 120 to be allowed to receive
data (i.e. to which selected communication device the data is
intended). 630 Optionally, the radio network node 140 selects the
first or second long identifier based on the selection of the first
or second communication device in step 620. 640 The radio network
node 140 sends a downlink message, including the multi-user-C-RNTI
and the first long identifier, to the first and second
communication devices 110, 120. The first long identifier enables
each of the first and second communication devices 110, 120 to
determine whether the downlink message was intended to it. 650 The
first communication device 110 checks whether the first long
identifier, comprised in the downlink message, is equal to the
first long identifier associated to the first communication device
110. Thus, the first communication device 110 may conclude that the
downlink message was intended to it. 660 Optionally, the first
communication device 110 may need to synchronize in case
synchronization has been lost.
In some embodiments of the method in the radio network node 140,
the multi-user-C-RNTI comprises paging radio network temporary
identifier, referred to as P-RNTI.
The C-RNTI is reserved, as explained in the embodiments above, for
a particular communication device only over a limited time period.
The reservation may be released when e.g. one of the following
events occur: 1. A C-RNTI release command received by the
communication device. The command is sent by the radio network node
and may be, e.g., a RRC command or a MAC Control element. 2. A
C-RNTI reservation timer expires. The specific C-RNTI timer is
defined for communication devices sharing C-RNTIs. The timer is
initially started when the C-RNTI contention is solved as described
above and may be restarted when a scheduling assignment is
received. The timer length is configured by the network. 3. The
Timing Alignment timer expires. 4. The communication device is not
active anymore as regard to DRX operation (see below). This may
happen when the DRX On Duration timer, DRX Inactivity timer, or DRX
Retransmission timer expires.
When the C-RNTI reservation ends, the communication device will not
listen to the PDCCH anymore until it again wants to transmit
something.
FIG. 7 shows a combined, signalling and flow chart of another
embodiment of a method in the radio network node 140, in which
method the concept of DRX is extended. The following step may be
performed. 710 The radio network node 140 configures a timer for
the first and second communication devices 110, 120, respectively,
wherein the timer is indicative of when the communication device
110, 120 is obliged to refrain from using the C-RNTI. See further
description of the timer below. 720 The first communication device
110 determines whether current time is within time period indicated
by the timer. When current time is within time period indicated by
the timer, the first communication device 110 is allowed to use the
first C-RNTI.
In this embodiment, the first and second communication devices 110,
120 are allowed to use the first C-RNTI only in certain time
periods as given by the timer. Outside of those times, the
communication devices 110, 120 are not allowed to use the first
C-RNTI (i.e. the shared C-RNTI). Allocation of time periods can be
done in multiple ways. One solution is to exploit the current DRX
procedure specified in LTE with modifications. Another solution is
to introduce new timers or rules for C-RNTI sharing.
There can be several time scales to do the time based C-RNTI
control as indicated by the timer. For example, the first
communication device 110 may be allocated to use the first C-RNTI
during daytime, e.g., from 8:00 to 20:00 and the second
communication device 120 could be allocated to use the same C-RNTI
during night-time, e.g., from 20:00 to 8:00. This way the
communication device (out of the first and second communication
devices), using the first C-RNTI, is always uniquely known and no
additional signalling (as in the embodiments above) to confirm the
identity of the communication device (by means of for example IMSI)
is needed. If desired, a guard period may be added to the switching
times. The guard period may be, for example, 1 minute when neither
of the first and second communication devices 110, 120 may be
allowed to use the first C-RNTI. Another example could be to allow
the first communication device 110 to use the first C-RNTI for 1000
ms at a time and the next 1000 ms are then allocated for use by the
second communication device 120.
Alternatively, the periods during which the first and second
communication devices 110, 120 are allowed to use the first C-RNTI
is defined based on a modulo operation on the System Frame Number
(SFN), where the SFN is a cyclic time-counter that is incremented
by one e.g. every 10th millisecond. For example, the first
communication device 110 may be configured to start using the first
C-RNTI when the following equation is satisfied: SFN modulo first
C-RNTI-cycle=first C-RNTI-offset, where the first C-RNTI-cycle and
first C-RNTI-offset may be configurable parameters.
In addition, a configurable parameter C-RNTI-duration may be
defined, that describes how many frames or subframes the first and
second communication devices 110, 120 are allowed to use the
aforementioned first C-RNTI. This parameter defines the first and
second communication devices 110, 120 to continue using the first
C-RNTI for a pre-determined number of subframes after each event
when the equation above is satisfied. By configuring multiple
communication devices that share the same identity, it is thus
possible to assure that two communication devices never use the
shared C-RNTI at the same time.
For example, if the first communication device 110 has the first
C-RNTI-cycle set to 512 and the first C-RNTI-offset set to 0, and
the second communication device has C-RNTI-cycle set to 512 and
C-RNTI-offset set to 256, and both the first and second
communication devices 110, 120 are configured to use the shared
first C-RNTI maximally 256 frames after the satisfaction of the
equation above, then it is ensured that the first and second
communication devices 110, 120 never use the shared first C-RNTI at
the same time. Specifically, the first communication device 110
will use the first C-RNTI during times when SFN is within the
intervals {0,255}, {512, 767}, . . . while the second communication
device 120 will use the first C-RNTI during times when SFN {256,
511}, {768, 1023}, . . . .
In the example above, the SFN is used as the reference for dividing
the use of the first C-RNTI over time. It should be understood that
the solution may be applied on any other time-granularity, such as
the sub-frame number, where each radio frame (SFN) is further
divided into subframes of 1 ms duration.
Here the standardized DRX mechanism is utilized in C-RNTI sharing.
It then needs to be further defined that when the first
communication device 110 is not active, the first C-RNTI, signalled
on PDCCH, is not valid for the first communication device 110,
i.e., the DRX is mandatory instead of optional. In addition,
transmission of the SR over RACH or PUCCH may be restricted to
certain periods or times. This period may be active time as defined
in DRX, or the On Duration time, which occurs in the beginning of
each DRX cycle.
Turning to FIG. 8, there is shown an arrangement 800 in the radio
network node 140 for sharing of a first Cell Radio Network
Temporary Identifier, referred to as "C-RNTI" between a first and a
second communication device 110, 120. The radio network node 140
may comprise the arrangement 800. A radio communication system 100
comprises the radio network node 140 and the first and second
communication devices 110, 120. The arrangement 800 may comprise a
receiving unit 810 configured to receive a first random access
preamble from the first communication device 110, and a processing
circuit 820 configured to associate the first C-RNTI to the first
communication device 110, in response to the first random access
preamble. The receiving unit 810 may further be configured to
receive a second random access preamble from the second
communication device 120. The processing circuit 820 may further be
configured to associate the first C-RNTI to the second
communication device 120, in response to the second random access
preamble, while the association of the first C-RNTI to the first
communication device 110 is maintained. Thus, the first C-RNTI is
shared between said first and second communication devices 110,
120. The processing circuit 820 may be realized by a processing
unit, a processor, an application specific integrated circuit
(ASIC), a field-programmable gate array (FPGA) or the like.
Moreover, the arrangement 800 may comprise a memory 830 connected
to the processing circuit 820. The memory 830 may store
instructions for performing embodiments disclosed herein, which
instructions may be executed by the processing circuit 820.
In some embodiments of the arrangement 800 in the radio network
node 140, the arrangement 800 further is configured to assign the
first C-RNTI to the first communication device 110 and to assign
the first C-RNTI to the second communication device 120, while the
assignment of the first C-RNTI to the first communication device
110 is maintained. The first and second communication devices 110,
120 are connected to the radio network node 140.
In some embodiments of the arrangement 800 in the radio network
node 140, the first and second communication devices 110, 120 are
associated to a first and second long identifier, respectively. The
first long identifier is different from the second long identifier.
The arrangement 800 is further configured to receive a third and a
fourth random access preamble, indicative of requests for sending
data, from the first and second communication devices 110, 120,
respectively. The arrangement 800 is further configured to send, to
the first and second communication devices 110, 120, a random
access response message in response to the third and fourth random
access preambles. The arrangement 800 is further configured to
receive, from the first communication device 110, a first message
including the first long identifier (1st long id.) in response to
the random access response message. The arrangement 800 is further
configured to receive, from the second communication device 120, a
second message including the second long identifier (2nd long id.),
in response to the random access response message. The arrangement
800 is further configured to send, to the first and second
communication devices 110, 120, a contention resolution message,
comprising the first long identifier, thereby allowing the first
communication device 110 to send data.
In some embodiments of the arrangement 800 in the radio network
node 140, the arrangement 800 further is configured to assign a
third and a fourth random access preamble to the first and second
communication devices 110, 120, respectively. The third random
access preamble is different from the fourth random access
preamble. The arrangement 800 further is configured to receive the
third and fourth random access preambles, indicative of requests
for sending data, from the first and second communication devices
110, 120, respectively. The arrangement 800 further is configured
to send, to the first communication device 110, a random access
response message including the third random access preamble, in
response to the third random access preamble. The arrangement 800
further is configured to receive, from the first communication
device 110, a first message including the first C-RNTI, in response
to the random access response message. The arrangement 800 further
is configured to send, to the first communication device 110, a
contention resolution message, comprising the first C-RNTI assigned
to the first communication device 110, which enables the first
communication device 110 to determine whether it is allowed or not
allowed to send data.
In some embodiments of the arrangement 800 in the radio network
node 140, the radio communication system 100 further comprises a
third communication device 130. The arrangement 800 further is
configured to receive a fifth random access preamble from the third
communication device 130. The arrangement 800 further is configured
to assign a second C-RNTI to the third communication device 130.
The arrangement 800 further is configured to assign the third
random access preamble to the third communication device 130.
Moreover, the arrangement 800 further is configured to send the
random access response message including the third random access
preamble to the third communication device 130. The arrangement 800
further is configured to receive, from the third communication
device 130, a second message including the second C-RNTI, in
response to the random access response message. Further, the
arrangement 800 is configured to send the contention resolution
message, comprising the first C-RNTI to the third communication
device 130.
In some embodiments of the arrangement 800 in the radio network
node 140, the arrangement 800 further is configured to associate a
second C-RNTI to the second communication device 120, whereby a
group of C-RNTIs, comprising the first and second C-RNTIs, are
associated to the second communication device 120.
In some embodiments of the arrangement 800 in the radio network
node 140, the first and second communication devices 110, 120 are
associated to a first and second long identifier, respectively. The
first long identifier is different from the second long identifier.
The arrangement 800 is further configured to receive a third and
fourth random access preamble, indicative of requests for sending
data, from the first and second communication devices 110, 120,
respectively. The arrangement 800 is further configured to send, to
the first and second communication devices 110, 120, a random
access response message in response to the third and fourth random
access preambles. The arrangement 800 is further configured to
receive, from the first communication device 110, a first message
including the first long identifier (1st long id.) in response to
the random access response message. The arrangement 800 is further
configured to receive, from the second communication device 120, a
second message including the second long identifier (2nd long id.),
in response to the random access response message. The arrangement
800 is further configured to send, to the first communication
device 110, a first contention resolution message, comprising the
first C-RNTI, which is to be assigned to the first communication
device 110, and the first long identifier, which indicates to the
first communication device 110 that it is allowed to send data. The
arrangement 800 is further configured to send, to the second
communication device 120, a second contention resolution message,
comprising the second C-RNTI, which is to be assigned to the second
communication device 120, and the second long identifier, which
indicates to the second communication device 120 that it is allowed
to send data.
In some embodiments of the arrangement 800 in the radio network
node 140, the first and second communication devices 110, 120 are
associated to a first and a second long identifier, respectively.
The first long identifier is different from the second long
identifier. The arrangement 800 is further configured to assign (or
associate in some embodiments) a multi-user-C-RNTI (MC-RNTI) to the
first and second communication devices 110, 120. The arrangement
800 is further configured to send a downlink message, including the
multi-user-C-RNTI and the first long identifier, to the first and
second communication devices 110, 120.
In some embodiments of the arrangement 800 in the radio network
node 140, the arrangement 800 further is configured to configure a
timer for the first and second communication devices 110, 120,
respectively.
In the embodiments of the arrangement 800 above, when expressed as
the arrangement 800 is configured to send, this may be realized by
a sending unit 840, comprised in the arrangement 800. The sending
unit 840, such as a transmitter, may thus be configured to perform
the steps of sending described above.
In the embodiments of the arrangement 800 above, when expressed as
the arrangement 800 is configured to receive, this may be realized
by the receiving unit 810, such as a receiver. The receiving unit
810 may thus be configured to perform the steps of receiving
described above.
Now referring to FIG. 9, there is shown a schematic flow chart of
an embodiment of a method in the first communication device 110 for
enabling sharing of a first Cell Radio Network Temporary
Identifier, referred to as "C-RNTI" between at least the first
communication device 110 and a second communication device 120. A
radio communication system 100 comprises a radio network node 140
and the first and second communication devices 110, 120. The first
C-RNTI is assigned to the first and second communication devices
110, 120. The first and second communication devices 110, 120 are
associated to a first and second long identifier, respectively. The
first long identifier is different from the second long identifier.
The following steps may be performed. Notably, in some embodiments
of the method the order of the steps may differ from what is
indicated below. 310 The first communication device 110 sends a
third random access preamble, indicative of a request for sending
data, to the radio network node 140. As an example, the third
random access preamble may be sent in conjunction with a Scheduling
Request (SR) on RACH or PUCCH (Physical Uplink Control Channel).
320 The first communication device 110 receives, from the radio
network node 140, a random access response message in response to
the third random access preambles. 330 The first communication
device 110 sends, to the radio network node 140, a first message
including the first long identifier in response to the random
access response message. 340 The first communication device 110
receives, from the radio network node 140, a contention resolution
message, comprising the first long identifier. 380 The first
communication device 110 checks whether the received long
identifier, comprised in the contention resolution message, is
equal to the first long identifier assigned to the first
communication device 110.
In FIG. 10, there is shown a schematic, exemplifying block diagram
of an embodiment of an arrangement 900 in a first communication
device 110 for enabling sharing of a first Cell Radio Network
Temporary Identifier, referred to as "C-RNTI" between at least the
first communication device 110 and a second communication device
120. A radio communication system 100 comprises a radio network
node 140 and the first and second communication devices 110, 120.
The first C-RNTI is assigned to the first and second communication
devices 110, 120. The first and second communication devices 110,
120 are associated to a first and second long identifier,
respectively. The first long identifier is different from the
second long identifier. The arrangement 900 may comprise a sending
unit 910 configured to send a third random access preamble,
indicative of a request for sending data, to the radio network node
140. The arrangement 900 further comprises a receiving unit 920
configured to receive, from the radio network node 140, a random
access response message in response to the third random access
preambles. Moreover, the sending unit 910, such as a transmitter,
is further configured to send, to the radio network node 140, a
first message including the first long identifier in response to
the random access response message, and the receiving unit 920,
such as a receiver, is further configured to receive, from the
radio network node 140, a contention resolution message, comprising
the first long identifier. Furthermore, the arrangement 900
comprises a processing circuit 930 configured to check whether the
received long identifier, comprised in the contention resolution
message, is equal to the first long identifier assigned to the
first communication device 110. The processing circuit 930 may be a
processing unit, a processor, an application specific integrated
circuit (ASIC), a field-programmable gate array (FPGA) or the like.
Moreover, the arrangement 900 may comprise a memory 940 for storing
software to be executed by, for example, the processing circuit.
The software may comprise instructions to enable the processor to
perform the method described above.
Even though embodiments of the present invention have been
described, many different alterations, modifications and the like
will become apparent for those skilled in the art. The described
embodiments are therefore not intended to limit the scope of the
invention, which is defined by the appended claims.
* * * * *